The motive of the shooting was not known but comes amid spiralling tensions across the city and the country between the black community and police. The races of the suspects and the officers were not immediately known.
Officials confirmed that three law enforcement officers died during an early morning shooting on Airline Highway in Baton Rouge, Louisiana, over a kilometre away from a local police station.
She said law enforcement officials believe there are at least two other shooters who may be at large. However, investigators were working to determine the exact number of shooters involved.
"We do know, and do believe there are more than one suspect. That's why we're alerting the community," said Cpl. L'Jean McKneely. "We sending in the robot to see if there are any explosives in the area or any explosives on him."
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Police received a call of "suspicious person walking down Airline Highway with an assault rifle," a source said, adding that when police arrived, the man opened fire.
White House has been in contact with local officials in Baton Rouge and has offered necessary assistance, the official said.
Louisiana Governor John Bel Edwards called Baton Rouge shooting an "unspeakable and unjustified attack on all of us".
"Rest assured, every resource available to the State of Louisiana will be used to ensure the perpetrators are swiftly brought to justice," Edwards said in a statement.
The victims were from Baton Rouge Police Department as well as East Baton Rouge Parish Sheriff's Office.
"I walked out into the street to see what was going on, there was a man lying in the street. I assume he was dead because he wasn't moving," a witness told WAFB-TV.
During a call to dispatch, an officer said, "unknown where the shots are coming from."
The injured policemen were reported to be in a critical
condition.
Baton Rouge City Mayor Kip Holden told local media that he was still gathering details on the total number of officers who were wounded in the shooting.
The shooting is the latest in a series of high-profile killings that have rocked the country recently that have exposed the undercurrent of racial prejudice and an epidemic of gun violence.
A gunman killed five police officers in Dallas earlier this month during a demonstration triggered by the fatal police shooting of two African-American men.
Over the weekend, thousands of people took to the streets in Baton Rouge to condemn Sterling's death. Authorities arrested about 200 people over the weekend.